Nearly 20% of primary PC carries genomic defects involving DNA damage repair (DDR) pathways: the most frequently P/LPVs occur in BRCA2 (3%), BRCA1 (1%), CDK12 (2%), ATM (4%), FANCD2 (7%), and RAD51C (3%) [4,5]. The gene discussed is BRCA1; the disease is pachyonychia congenita.